Solve for $n$ : $n - 17 = -30$
Answer: Add $17$ to both sides: $ \begin{eqnarray} \\ n - 17 &=& -30 \\ \\ {+17} && {+17} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-17 + n} &\hphantom{=}& \hphantom{-30} \\ n &=& -30 {+ 17} \\ \end{eqnarray} $ Simplify. $ n = -13$